Around 100 km diameter would boil the oceans. It is possible that a bunker in Antarctica that can handle hundreds of atmospheres of pressure (due to the oceans being above us in vapor form) could work. But it would have to last for something like 1000 years. Or we would have to stay on Mars for 1000 years.
If it’s so big no bunkers work, how long would we have to wait on Mars before coming back?
Around 100 km diameter would boil the oceans. It is possible that a bunker in Antarctica that can handle hundreds of atmospheres of pressure (due to the oceans being above us in vapor form) could work. But it would have to last for something like 1000 years. Or we would have to stay on Mars for 1000 years.